Fsmash is more as a spacing too than a punishing tool. Don't try to use it to punish if the opponent is really close. Dsmash, Usmash, Fair, grab are all better options.
While shielding is good, don't sit in it for too long. Olimar has mediocre tools after a shield drop. His moves aren't the fastest, and have bad priority. When you're in a shield, constantly look for ways to get away from the opponent, it's important. While rolling is bad, doing it at times can be beneficial, if not predicted, and when there are no other options.
You aren't camping the falco. Throw Pikmin from the ground, and make him come to you. Don't dash grab with Olimar, it's not very good. Dash Grab is a punishing tool at best. It comes out extremely slow, doesn't have as much range as a regular grab, is really laggy, and leaves you right next to your opponent which is not where you want to be.
You're good at baiting, especially when the opponent is landing. Keep it up, make sure you know all of your punishing options, though.
So yeah, pikmin toss a lot more. Start using fair more often. Other than that you're really not bad, tbh :O
I'll see if there's anything else I can think to say for critique. Welcome to the Oli Boards!